Re: [PATCH v4 13/15] fanotify: support events with data type FSNOTIFY_EVENT_INODE

[Jan Kara <jack@suse.cz>]

On Sun 02-12-18 13:38:24, Amir Goldstein wrote:
> When event data type is FSNOTIFY_EVENT_INODE, we don't have a refernece
> to the mount, so we will not be able to open a file descriptor when user
> reads the event. However, if the listener has enabled reporting file
> identifier with the FAN_REPORT_FID init flag, we allow repoting those
							 ^^^ reporting

> events and we use an indentifier inode to encode fid.
			^^ identifier

> The inode to use as indetifier when reporting fid depedns on the event.
			^^ identifier			^^ depends

> For dirent modification events, we report the modified directory inode
> and we report the "victim" inode otherwise.
> For example:
> FS_ATTRIB reports the child inode even if reported on a watched parent.
> FS_CREATE reports the modified dir inode and not the created inode.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
...
> @@ -201,13 +202,34 @@ static int fanotify_encode_fid(struct fanotify_event *event,
>  	return FILEID_INVALID;
>  }
>  
> +/*
> + * The inode to use as indetifier when reporting fid depedns on the event.
			  ^^ identifier			^^ depends

> + * Report the modified directory inode on dirent modification events.
> + * Report the "victim" inode otherwise.
> + * For example:
> + * FS_ATTRIB reports the child inode even if reported on a watched parent.
> + * FS_CREATE reports the modified dir inode and not the created inode.
> + */
> +static struct inode *fanotify_report_id(struct inode *to_tell, u32 event_mask,
> +					const void *data, int data_type)
> +{
> +	if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
> +		return to_tell;
> +	else if (data_type == FSNOTIFY_EVENT_INODE)
> +		return (struct inode *)data;
> +	else if (data_type == FSNOTIFY_EVENT_PATH)
> +		return d_inode(((struct path *)data)->dentry);
> +	return NULL;
> +}
> +

Maybe call this function fanotify_fid_inode()?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR